| 1. |
- Atashipour, Rasoul, 1983, et al.
(författare)
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Simulation and analysis of adhesive failure in Glued-in Rod (GiR) connections for timber structures
- 2019
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Ingår i: Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019. - : CRC Press. - 9781138386969 ; , s. 1768-1773
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Konferensbidrag (refereegranskat)abstract
- Adhesive joints have been known and used in different applications within the area of structural and mechanical engineering for decades. Hybrid joints with glued-in rods are nowadays increasingly used as an efficient way for both constructing new and strengthening/repair of existing timber structures. However, despite ongoing research since the 1980s, general and reliable design criteria for such connections are missing in the European standard for timber structures, Eurocode 5, and there is contradiction between the load bearing capacity predicted by different existing design models. In this study, the adhesive bond-layer failure, as the dominant failure mode in GiR connections, is simulated for single- steel rod joints based on the nonlinear elastic fracture mechanics (NLEFM) approach using Abaqus software. A finite element (FE) model, describing timber-adhesive interface failure, was established, calibrated as well as verified through comparison with existing test results reported in literature. The simulations are conducted for two different types of adhesives namely epoxy (EPX) and polyurethane (PUR). The single- GiR joints are loaded in axial tension and progressive failure is simulated to accurately predict the maximum load bearing capacity of the joints due the pull-out failure, in the timber-to-rod adhesive bond layer. A parameter study was conducted and the influence of some geometrical dimensions and material property parameters on the pull-out capacity of single-rod connections is investigated. It was shown that simplified axisymmetric models can also accurately describe the behaviour of single GiR connections when compared with a more realistic 3-D model, with significantly less processing time and computational effort.
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| 2. |
- Lim, Hyeong Uk, et al.
(författare)
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A surrogate model to describe uncertainties in wood floor modal frequencies
- 2019
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Ingår i: Advances in Engineering Materials, Structures and Systems : Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019 - Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019. - : CRC Press. - 9781138386969 - 9780429426506 ; , s. 121-126
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Konferensbidrag (refereegranskat)abstract
- Wooden multi-story buildings have increased their market share in Europe over the last decades, mainly due to their relatively small carbon footprint and rapid onsite construction. Compared to more conventional heavy concrete buildings, wooden buildings are more sensitive to dynamic loads at low frequencies. Moreover, the dynamic response is generally more difficult to predict. This is, for example, due to the variability in the material properties of wood. Since wood is a natural material, local variations in performance occur, even if selected members are taken from the same batch. Also, the cut and treatment of individual members have an impact, and material properties can vary with time due to changing moisture content and aging effects. In this study, we investigate the effect of variability in material properties of joists on the dynamic modal characteristics of wood floors with the help of surrogate models, constructed using polynomial chaos expansion (PCE). These surrogate models are based on computations that use a dynamic reduced-order finite-element (FE) model, calibrated to produce modal outputs consistent with floor vibration experiments. Uncertainty in modal frequencies of the wood floor systems based on the PCE surrogate models is consistent with that found using the FE model in Monte Carlo simulations, which serve to define the “truth” model. However, PCE surrogate models offer significant reduction in computation time compared to FE models, when uncertainty in dynamic behavior needs to be quantified.
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| 3. |
- Malmborg, J., et al.
(författare)
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Evaluating the effect of vibration isolation mats on train-induced ground vibrations
- 2019. - 1
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Ingår i: Advances in Engineering Materials, Structures and Systems : Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019 - Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019. - : CRC Press. - 9781138386969 - 9780429426506 ; , s. 85-90
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Konferensbidrag (refereegranskat)abstract
- In the present paper, the effectiveness of a vibration isolation mat for a railway slab track system is studied using a finite element model of the railway track. The finite elements are formulated in a moving frame of reference following the moving load at a particular speed. The rails are modeled using Bernoulli beams, whereas the track slab and an underlying supporting plate are modeled using Kirchhoff plate elements. The vibration isolation mat is modeled as a continuous visco-elastic layer between the track slab and the supporting plate. The response of the underlying soil is represented through a dynamic stiffness matrix, obtained via the Green’s function for a horizontally layered visco-elastic strata in a moving frame of reference in the frequency– wavenumber domain. The model accounts for the quasi-static excitation caused by the static axle loads of a vehicle, as well as the dynamic excitation caused by the vehicle running over an uneven rail. The free-field response and the insertion loss obtained with the vibration isolation mat is first evaluated for a harmonic load moving along the track. Band-averaged vibration levels and the insertion loss for a fixed point next to the track are then calculated for a train cart, represented by a 10 degree-of-freedom multi-body system, running at different speeds.
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| 4. |
- Persson, P., et al.
(författare)
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A surrogate model for vibration transmission in layered soil
- 2019. - 1
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Ingår i: Advances in Engineering Materials, Structures and Systems : Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019 - Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019. - : CRC Press. - 9781138386969 - 9780429426506 ; , s. 31-36
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Konferensbidrag (refereegranskat)abstract
- Ground vibration from traffic or construction work in cities is a known source of annoyance to inhabitants. However, vibration and re-radiated noise in buildings caused by exterior sources are seldom treated properly in the design process, which may be due to the lack of methodologies that can aid informed decision-making with respect to environmental vibration. To achieve efficient evaluation of ground vibration levels, the present paper proposes the use of surrogate models for evaluation of the transmission loss in one-third octave bands at a given distance from a vertical source on a layered ground. Polynomial Chaos Expansion is employed, and the frequency range relevant to human whole-body vibration is considered, i.e., 1–80 Hz. Stochastic variability in soil properties is propagated to variability in transmission losses, and the quality of the PCE models is assessed by comparison with results obtained by crude Monte Carlo simulation.
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| 5. |
- Persson, P., et al.
(författare)
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Influence of uncertain parameters on modal properties of wood floors
- 2019
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Ingår i: Advances in Engineering Materials, Structures and Systems : Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019 - Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019. - : CRC Press. - 9780429426506 - 9781138386969 ; , s. 127-132
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Konferensbidrag (refereegranskat)abstract
- The use of wood as load-bearing material in residential and office buildings has increased significantly in Europe over the last decades. Such buildings often have wooden floors built with boards supported by joists and/or beams. The modal properties of such floors are important regarding the floors’ dynamic response to walking and other usage as well as structure-borne vibration and re-radiated noise from sources placed elsewhere inside or outside the building. Wood buildings are more sensitive to dynamic loads than heavier concrete buildings. Moreover, it is more difficult to predict accurate vibration levels in wood floors because they are complex structures involving many connections that vary in their mechanical behavior and because of the large variability in the material parameters of wood. In this study, a finite element model is used to investigate the effect of variability in material parameters of structural members on a timber floor’s modal properties. In order to propagate the variability in the material parameters to the floor panel’s eigenfrequencies, probabilistic analysis is conducted using Monte Carlo simulations.
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| 6. |
- Possidente, Luca, et al.
(författare)
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A 3D beam element to study torsion of steel open sections exposed to fire
- 2019
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Ingår i: Advances in Engineering Materials, Structures and Systems. - : CRC Press. - 9780429426506 - 9781138386969 ; , s. 561-565
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Konferensbidrag (refereegranskat)abstract
- In the analysis of structures in fire, numerical models must account for the effects of increasing temperatures. Although different finite elements capable of effectively tackling the problem are available, 3D beam elements employed in many commercial software do not properly account for the degradation of the torsional properties with temperature. In this context, an enhanced 3D beam element based on a co-rotational formulation is proposed. The element was specifically developed for steel elements and is well suited for the analysis of structures that exhibit a significant torsional behavior. The Timoshenko beam theory was employed and the steel stress-strain law and thermal expansion were implemented according to EN1993-1-2. Two different case studies are presented in this paper. Numerical analyses by means of two different software (ABAQUS and SAFIR) were performed and compared to the results. The outcomes confirmed the effectiveness of the proposed element.
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| 7. |
- Sciegaj, Adam, 1990, et al.
(författare)
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Two-scale modelling of reinforced concrete deep beams: Choice of unit cell and comparison with single-scale modelling
- 2019
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Ingår i: Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation, 2019. - : CRC Press. - 9781138386969 ; , s. 251-256
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Konferensbidrag (refereegranskat)abstract
- Two-scale and single-scale models are used to analyse the response of reinforced concrete deep beams with different reinforcement layouts. To this end, a novel approach of modelling non-uniformly reinforced structures in a multiscale manner is developed. Parameterised generation of suitable unit cells is described, and the subdivision of problem domain into regions with different substructures is presented. Three different reinforced concrete deep beams with available experimental data are analysed. Mid-span deflections are slightly underestimated by both models, while the maximum load is captured reasonably well.
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| 8. |
- Tell, Sarah, et al.
(författare)
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Real-time hybrid simulation of a bridge-damper system
- 2019
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Ingår i: Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications: Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation (SEMC 2019), September 2-4, 2019, Cape Town, South Africa. - Cape Town : CRC Press. - 9781138386969 ; , s. 1810-1813
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Konferensbidrag (refereegranskat)abstract
- This paper presents the use of external dampers for vibration mitigation of railway bridges subjected to passing trains. A numerical model of the bridge combined with an experimental setup of a full-scale magnetorheological damper is used. The combined bridge-damper system is analyzed in real-time using a hybrid simulation technique. The approach is illustrated on a simply supported steel-concrete composite bridge. Due to the large eccentricity between the neutral axis and the roller support, the resulting displacement motivates the use of a near support damper. It is shown that sufficient vibration mitigation can be obtained with a single damper. A parametric study is performed to determine the optimal damper position and inclination.
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